1. Field of the Invention
In one of its aspects, the present invention relates to a fluid treatment system, more particularly, an integrated system that treats water by filtration and by exposure to radiation, preferably ultraviolet radiation. In another of its aspects, the present invention relates to a method for treating a fluid, more particularly a method for irradiating water.
2. Description of the Prior Art
Fluid treatment systems are generally known in the art. More particularly, ultraviolet (UV) radiation fluid treatment systems are generally known in the art. Many of the known radiation treatment systems have been designed for treatment of large volumes of fluid (typically wastewater) on a commercial scale. Thus, many of these known fluid treatment systems have been implemented in municipal wastewater treatment plants (i.e., treatment of water that is discharged to a river, pond, lake or other such receiving stream), municipal drinking water treatment plants, industrial wastewater treatment plants and the like.
For examples of fluid treatment system that have been applied in municipal wastewater treatment plants, see U.S. Pat. Nos. 4,482,809, 4,872,980, 5,006,244, 5,418,370, 5,539,210 and Re 36,896 (all in the name of Maarschalkerweerd and all assigned to the assignee of the present invention) which describe gravity fed fluid treatment systems which employ ultraviolet (UV) radiation.
In the field of municipal drinking water, it is known to utilize so-called “closed” fluid treatment systems or “pressurized” fluid treatment systems. Closed fluid treatment devices are known—see, for example, U.S. Pat. No. 5,471,063 (in the name of Hayes et al. and assigned to the assignee of the present invention) and U.S. Pat. No. 5,504,335 (in the name of Maarschalkerweerd and assigned to the assignee of the present invention). See also U.S. Pat. No. 6,500,346 [Taghipour et al. (Taghipour) and assigned to the assignee of the present invention].
In recent years, notwithstanding the significant advances made in fluid disinfection technology useful for treating municipal waste water and municipal drinking water, there has been an increasing need to improve the quality of water used on a domestic basis. This is led to a boom in the bottled water industry.
In other words, even though government agencies have implemented stringent guidelines for treatment of water in municipal drinking water plants thereby improving the quality of water delivered to domiciles, the heightened awareness of having “purified” drinking water for domestic use has at least been responsible for the boom in the bottled water industry. Reliance on bottled water for drinking is fraught with a number of disadvantages, including:                on a volume basis, bottled water is very expensive (typically, in many countries, the cost of bottled water exceeds the cost of fuel used to power automobiles);        it is inconvenient to obtain (i.e., the user must purchase the bottled water in a desired volume, transport the volume to the domicile, etc);        it requires adequate storage space in the domicile; and        it creates an environmental issue in that empty bottles must be discarded after use.        
An alternative to using bottled water is to utilize filter units available from retail outlets. Non-limiting examples of such filtered units include the Brita™ system, the Moen™ filter system and the like. Typically, these filter systems may involve a cartridge element which is placed in a pitcher or other container for water or they are fixed to a faucet. Unfortunately, while these filter systems are useful to remove particulates and, in some cases, “taste” and/or “odour” from the water being treated, they are unable to remove many micro organisms. In addition, some filter systems are disadvantageous since the filter media itself is susceptible to collection, growth and/or release of the very microorganisms which are removed from the water.
Another approach which has been used domestically is a radiation treatment system which can be obtained from a retail outlet and installed under a kitchen counter or elsewhere in the domicile. Such systems are particularly useful in disinfecting or otherwise inactivating microorganisms in the water. Unfortunately, these systems do not remove particulate matter and other non-living contaminants that may be present in the water.
Thus, there remains a need in the art for a relatively small scale water treatment system which can receive municipal drinking water and treat that water to remove (or at least reduce to a low level) contaminants that may be present in the drinking water—e.g., microorganisms, particulate material, non-living contaminants (e.g., organic compounds, oxidants and the like). It would be particularly useful to have such a device sized and styled in a matter that can be used as an “on-the-counter” appliance in a domicile. In addition, it would particularly beneficial if such a system were relatively low maintenance, easy to install and easy to use.